Maximum bond angle is present in

Among the following,the bond angle is minimum between:

Fill in the blanks:
$(i)$ In $1927$,Heitler and London proposed the ........ theory.
$(ii)$ The ${\rm{ClF}}_3$ molecule has a .... shape.
$(iii)$ The number of bonding pairs in ions with a square planar shape is .......... .
$(iv)$ The value of the dipole moment in ${\rm{HBr}}$ is .......... .

The correct order of increasing bond lengths of $C-H$, $O-H$, $C-C$ and $H-H$ is

Identify the odd-electron molecules among $NO$,$NO_2$,$CO$,and $CO_2$. Explain why.

The number of $S-S$ bonds in sulphur trioxide trimer $(S_3O_9)$ is